Para/Medic: Syrinx and Pain

Q. In March 2006 I became a T5 incomplete para from a motorcycle accident. A year later I started having numbness and “burning pins and needles” pain in my arms. By September 2007 the pain and numbness had gotten much worse. An MRI confirmed I had an elongated syrinx that went above and below T5. I underwent surgery and had a shunt put in, and the shunt relieved the pain and numbness. But this summer the burning pins and needles returned and got worse over time. I also developed a pressure sore that required hospitalization. A follow-up MRI confirmed that I had had a syrinx but the shunt had cleared it up. Now I’m wondering if the surgeon should have de-tethered my spinal cord as well.
— Dave, Loganville, Georgia

A. Dave, this is a complicated subject. Approximately 15 percent of people with SCI develop symptoms from spinal cord tethering or tethering with a syrinx that require surgical intervention. In the United States there are only two neurosurgeons at major rehab centers who specialize in performing surgery on tethered spinal cords and syrinxes — Dr. Barth Green at the University of Miami School of Medicine and Dr. Scott Falci at Craig Hospital in Denver.

According to Falci, who has performed over 1,000 surgeries on syrinxes and tethered spinal cords, a traumatic injury to the spinal cord causes scarring and tethering. A normal spinal cord moves back and forth a couple of millimeters with each heartbeat. It also moves in the spinal canal with body movement. With scarring, normal movement is impeded (the cord becomes tethered). The scarring also interrupts normal flow of spinal fluid around the cord. This may cause a breakdown in cell structure and spinal fluid will seep into the cord, resulting in softening of the spinal cord (myelomalacia). If enough fluid seeps in, a cyst or cavity may form (syrinx).

It is possible to have a syrinx but no symptoms. “The symptoms drive us to do the surgery,” Falci says. “I have heard people say, ‘I’ve had a huge syrinx on my cord for 20 years and the doc says if I don’t get it treated, I’m going to stop breathing and die.’ I tell them that’s not the way it works. If you’re not having symptoms, then leave it alone.”

What are the symptoms? First, tethering alone can cause the same symptoms as a syrinx, and they can be reason enough to decide to do the surgery. “Classic symptoms we see with a tethered cord or syrinx are not present at the onset of the injury but appear later,” Falci says. “They can include progressive loss of strength, progressive loss of sensation, progressively more or worse spasms, new or worsening neuropathic pain, unexplained autonomic dysreflexia and sweating. Once we have a proper history that points to a tethered cord or syrinx, next we rule out other things that can cause the same symptoms.” A syrinx can develop above the injury level, below, or both. He has seen tethering and syrinxes that require surgery appear as early as three months after injury and as long as 40 years later.

Any surgery has risk, and this is a very technical and lengthy surgery — about six hours on average. The most common reason people have the surgery, according to Falci, is for loss of sensory and or motor function. The second most common reason is for neuropathic pain (burning pins and needles is one form of neuropathic pain). Falci’s success rate at stopping further progressive loss of function is about 90 percent. He cautions this surgery should be done by a surgeon who is very experienced in the procedure, knows the indications of why you do the surgery, and has a history of good results. A large percentage of people he operates on have had one or more SCT/syrinx surgeries at other facilities, but only 10 percent return for recurring problems.

“During surgery I release (remove) scar tissue, take traction off the cord and the roots to try and make it more elastic and to correct the pressure differential across the injury site,” Falci says. “Then I place a graft of unscarred dura — the thick outermost layer covering the spinal cord — to minimize the chance of scar tissue forming again. If there is a syrinx, many times it will simply collapse right before my eyes just by releasing the scar.” Only about 20 percent of people with a syrinx require a shunt. Falci says the above procedure for untethering is the ideal, but there are circumstances where placing a shunt can be very effective if done properly and for the right cases.

With spasticity and neuropathic pain, Falci says, you first have to rule out other causes, such as any noxious stimuli to the body, like UTIs, bladder or kidney stones, and pressure sores. Then you determine if it can be controlled pharmacologically with baclofen pills or a baclofen pump, which have a 90 percent success rate of getting rid of spasticity. Untethering surgery has a 70 percent success rate. Discussing pain management options with a pain specialist or physiatrist who specializes in neuropathic pain is recommended because the success rate in untethering surgery for neuropathic pain is only about 50 percent.

Advice in this column is supported by Craig Hospital’s SCI Nurse Advice Line, a toll-free hotline for people living with spinal cord injury, a community service partially funded by grants from the PVA Education Foundation, Craig H. Nielsen Foundation and Caring for Colorado Foundation. For non-emergency nursing information about SCI health, call 800/247-0257 between 9 a.m. and 4 p.m. Mountain Time. If you have a health question, contact Bob Vogel at rhvshark@mac.com.